Conveyer furnace



Aug. 23, 1932. J. c. WOODSON CONVEYER FURNACE Filed March 17. 1930 3 Sheets- Sheet l #KNVENTOR James C. Woodson.

ATT'ORNEY Aug. 23, 1932. WOODSON 1,873,239

GONVEYER FURNACE Filed March 17, 1930 5 Sheets-Sheet 2 la g1 INVENTCR James C. woodson Ai'TORNEY Aug. 23, 1932. c WQQDSQN 1,873,239

' CONVEYER FURNACE Filed March 17, 1930 3 Sheets-Sheet 3 Fig. 5.

INVENTOR James CIA/000 5072.

A'TTORNEY Patented Aug. 23, 1932 UNITED; s r-Ares. PAT cargoes-ice] JAMES C. woorson, 0F MANSFIELD, oe o essence Memra reeia hearers. e sweetener: 0R PENNSYLVANlA onverse Application filed March 1 7, 193 s r al No. 43,369.

My invention relates to furnaces and particularly to-conveyer-type furnaces.

An object of my invention ist'o provide a relatively strong furnace structure that shall ensure the maintenance of the initial relative positions of the various parts of the furnace structure under normal varying operating conditions.

Another object of my invention is to-providea double-chamber furnace. structure having an intermediate wall, including a pluraliity of arches, that is. shorter than the outside wallsand is provided. with means for preventing excessive elongation.

Another object of my invention is to pro: vide a relatively simple overhanging roof structure of refractory material that. shall be so constructed as to be substantially rigid underthe various conditions of operation.

Another object of my invention is to pros vide a roof structure for a conveyer-type furnace having at least one slot in the .roof thereof which shall include interfitting refractory slabs of fire clay and. an armored concrete bonding mass located thereon as well asv resilient supporting means for the refractory roof'slabs.

Another object of my invention is to pro- Vide a slot-closure means supported :byuthe stationary furnace structure and movedby the conveyer over the walls of the slot, in combination with slot seals to prevent dust from dropping through the slot upon work being treated in the furnace.

In practicing my invention, Iprovide a relatively long furnace structure including a double chamber having suitable heating means in the central portion ofsuchstructure', as well as pre-heating chambers at the respec.- tive ends of the heated chambers, the intermediate wall being solid in the heated portion of the furnace and being relatively open and including arches in the pre-heating portions.

Longitudinally-extending slots are provided in the roof structure,and an endless conveyer or a plurality of suchconveyersare supported by a skeleton-frame structure as? sociated with therefractory structure ofthe furnace, the conveyer chains being provided Fig. 4 is a'view, in verticallat'eral section,

with dependfmg material-supporting rods which extend into, and move through there;

spective furnace chambers.

Inthe drawings,

Figure 1 isa top plan view of One-halfof afurnace assembly embodying my invention,

aportiononly of the con'veyer chains; being.

illustrated: Fig 2 isa vei lw, in'rertieal lo gitudinal sec: tion, taken on the line II+1 I ofF 1,

h Fig. 3 1's a view, in, vertical lateral-section, through a furnace embodying my invention, taken on the line III-III of Fig. 2,

taken on theline IV-IV of ig. '2,

Fig. 15 is a view, in vertical lateral section, taken on the line Vj-V of Fig. 2,

-F 1g. 6 is a fragmentary view, in, vertical at al section, on an e arged alato Show. t e. fu na c ns uction imm i te y aidia ent a slot, V i r Fig. 7 is a nag r e lta y i wyi erti al at a e ti n, of -a portion of the furnace str ucture to show the ,COI Struction of the slot closure means a d of e ma e ialuppo t ng means,

Fig. 8 is a view, in sideelevation, :ofa material-supporting bar,

, Fig.9 isa view, in-perspective, of two re.- fractory fire-clay 110 f slabs, y

' Fig; 10 is a View, in sideelevation, o'fa hook holder, and, y

holder.

' Referri-n g more particularly to Figs. land 2 of the drawings, 1 have there illustrated,

in top plan View and in vertical longitudinal sect on, respectively, a double-h atingchamb-er conveyer-type furnace particularly adapted for enameling Work. The furnace Fig. 11 is, a view, in endelevation, of a hook may have their lower ends embedded in a concrete :base 12 whichiextends below sub stantially all of the furnace.

e Horizontally.extendingmetal membersrlfi,

which may also 'be. of I-beam shape, have their. ends connected, :by suitable gusset plates 14,1tothe upperends OflthQIIIQIIIbBIS-ll. The

locationof the'vertical members 11 is, of

course, adapted to the various wall thickness of the different portions of the furnace,as

will be hereinafter pointed out more particularly in detail, and as is shown in the top plan View in Fig. 1 of the drawings.

Referringalso to Figs. 3, 4 and walls 17 and 18 and an intermediate-wall 19,

the side and bottom wall structures including an inner layer 21 of high-temperature resisting refractory bricks or blocks, and the intermediate wall being constructed entirely of such high-temperature resisting bricks.

Heat-insulating refractory material is then locatedoutside of the inner layer 21 which may consist of a plurality of bricks or blocks of proper refractory material or it may be made of monolithic material, as may be found desirable. Powdered refractory heatinsulating material 23 is located between the outer layer of solid heat-insulating material and a metal casing 24 which is, in turn, supported by the skeleton metal-frame structure I hereinbefore described;

Referring more particularly to Figs.- 3 and 4 ofthe drawings, I have there illustrated a roof structure which I-have found to be high- 'lysefli'cient in operation and whichis constructed to permit of maintaining the initial positions of all of the component parts with a minimum amount of shifting or variation in these relativepositions under'the varying conditionsof operation of the furnace; To this end, the roof proper consists of'a plu:

rality of inter-fitting slabs or blocks 26 of. 'fire clay, shown more particularly in Fig. 9

of the drawings. As there shown, each slab orblock is of substantially wedge shape and is provided with an upstanding flange 27 at its thicker edge.

A groove 28 is provided in one side, and a I corresponding and cooperating tongue 29 is providedi'at the other side so that the adjacent slabs 26 may be interlocked, as shown. A vertical semi-cylindrical recess 31 is provided at the side and adjacent to the forward side of each-slab, for a purpose to behereinafter set forth. A lateral groove'32 is provided in the upper face of each slab or block 26 and adjacent to its thin edge, for a purpose to be hereinafter set forth in detail. a

The thick ends of the slabs 26-so rest upon one'of the walls of the furnace as to overhang the respective furnace chambers, which have been designated as 33 and 34 in Fig. 3 of V the drawings. While the generalshape of lateral section. v V

the furnace chambers may vary to a slight de gree, the aligned-furnace chambers are of substantially the same general contour in Referring to Fig. 3 of the drawings, a monolithic mass36 of concrete overlies the slabs 26,that rests uponthe wall 17, this mass -36 interfitting with the flanges 27-on the re- 5, the furnace proper includes a floor 16, vertical side 7 1,873,239 I Jr; 2.1. l

spective slabs 26, aswell as resting upon the upper edge portion of the outer part of the solid wall 17. In order to strengthen the mass 36, Iprovide an armor in the shape of a coarse wire screen 37.

Similar slabs 26- are located with their thick endson the intermediate wall 19 in oppositely extending and abutting relation, as is shown in Figs. 3 to 5, inclusive. A monolithic mass 38 of concrete is provided over the major portion of eachof the sets of abutting slabs 26, and an armor 39 is provided therein, in substantially the manner,

and for the purpose, hereinbefore described.

for roof structure.

A snnilar mass 366; of'armored concrete 18 provided. over the side wall 18 and, as these roofip'ortions are alike, further description of this'part of the'st'ructure is unnecessary.

The granular refractory heat-insulating material 23extends over. the upper surface -of the monolithic Slabs-3G,.andsimilar grann lar heatinsulati.ngmaterialis provided over the central monolithic mass 38. v f

; The sets of..slabs;26,restmg, respectively, upon one of the outside walls and upon the intermediate. wall and extending toward each other, have their lnner ends spacedapart a predetermined distance in order to'cooperate with other elements to 3 be hereinafter described to provide a longitudmally-extend ing slot inthe roof structure, there being-two such slots 41 and 42' to correspond to the.

hand and :theconcretemass 38 on the other side-extend up to the members 43 andfwill,

therefore, be bonded therewith during the course of manufacture of-this part of the roofstructure,'1n a manner well known in the artu AI pluralityflof br)x like frames, each of skeleton construction, are provided -immediately above the roof of the furnace, there beingan intermediate frame structure 46 and two outside and similar frame structures 47. The intermediate frame structure 46 includes two angularly disposed cross braces 48'and 49, vertical metal members 50 and 51 and ,a' lower horizontal metalmemberj52, all of these metal members being suitably riveted together, as shown in Figs. 3. and-,4 of the drawingsg.

The outside frames 47-ineluderdepending vertical members-53, a 'diagonal bracing -1; I

wmem ber .54and a. horizontal lower me mberfl 1.56. The horizontal members 52 and 56interfit'with the roof structure to a certain degree, a

the furnace Chambers. zAs-was hereinbefore s the T-barsconstituting theseelements may. bepartially embedded in the refractory heatthat is,--one of the webs of the angle bars or .insulating material at the top of the roof ,proper. V

Longitudinal metal members 58 are'provided-adj acent tothe upper edges of the respectiveslots 41 and 42,.each of these membersbeing of substantially Z-shapeinlateral resp onding members. 53, and their lower webs are in operative engagement with the upper edges ofthe members 43 in order to so .defi-.

74 nitely locate and hold them in their proper operative and spaced positions relative to each other as-to define a longitudinally extending slot of a predetermined width.

It may be noted that the cross braces 48, 14:9 and 54 inthe respective skeleton frames are properly located to assist in supporting the vertical members 51 and 53 to cooperate with the roof structure and, more particu-.

larly, to prevent any weight from being placed upon the refractory roof structure.

As a furthermeansfor supporting the projecting' or overhanging roof structures, I have provided resilient supporting means including a plurality of rods 61 having Venlarged heads 62 at their lower ends, a. plate 63 being located between the head 62and a pair of adjacent slabs 26,:the rods 61 extending through the cooperating grooves 31 provided in adjacent edge portions of the slabs 26. 9

A structural-steel member 68, which may be of angle-bar shape in lateral section, extends longitudinally of the furnace structure and is riveted or otherwise secured to the members 52 or 56.

'A plurality ofmembers 65,,each of substantially angle-bar shape,have upper edges a. of hook shape to engage'th upper edge. of angle-bar member 68. The upper ends of rods 61 extend through openings in web portions'of the members 65, springs 64 being lo- .cated around their projecting ends; Nuts 66 i and washers 67 are providcdfor the purpose of drawing rods upwardly. The springs 64 permit of relative expansion and contraction of the various portions of the furnace frameand-roof assembly. I

Reference may now be had to Fig. 2 of the drawings and more particularly to the intermediate wall which is designated generally as 66a and which comprises a plurality of s arches 67a, each being built of suitable refractory bricks or blocks, in a manner well I known intheart, and resting upon refractory lbases' 68a which,in turn, rest upon there- C3 ,fractory floorstructure'16,which mayeither i is to be obtained when the furnace is in opera be special to the preheating chambers located at each endof the heating chambers-hereinbefore set forth or may be common to all of stated, the intermediate wallL19 is substan .tially solid, asitis desiredto provide two separate heating chambers, while; itis .necessary to provide. communicating chambers located in side-by-side relation if. recuperation tion. .Hence, I prefer to provide an 1ntermediate J wall structure. of substantially. the section,,as may best-be understoodby refer- -,ence to Fig. 6 of the drawings. The upper; vertical webs of the respective members58 may .be riveted tothe lower ends of the corsame general character as: are the outside :wall structures but of aniinterrupted character, that is, provided with-open spaces-00v ered by arches, in order that the heat-treated material, such as members which-have had enamel baked thereon,f.may give upaan appreciable portionof theirheatto incoming -material which is yet to-be iheatr'treated or su enameled. i V.

The intermediate wall structure, including thecentral portion 19 andtheendportions 66a, is made shorter than are the outside wall; portions in order that the extreme outer end flo portions of the furnace structure may not have any. wall intermediate the outside walls. The intermediate wall structure will, of course, expand and, in order that it may not expand to an undesirably high degree and in es order to anchor the ends thereof, I provide a vertical structural metal member, which maybe of I-shape in lateral section and is designated bythe numeral 71 in Fig. 2 of the p e drawings, the lower end being anchored in""1 the concrete base 12. A diagonally extending brace 72, which may also be of I-shape in lateral section-,is provided and has its upper end suitably secured to the upper end of member 71, while its lower end extends into" the concrete base to be firmly anchored therein. It is apparent that any longitudinalexpansion of the wall 66a and perhaps also of the wall 19 willbe resisted bythe brace 72 and at least a portion of this eXpansion-will-no be taken up by relatively small vertical movements of the individual refractory arches 67a, so that there will not be an excessive or multiplied movement of any part ofthe wall but rather this movement will be forcibly-$ sub-divided into a plurality of relatively small individual movements of portions of the wall in substantially an upward direction.

I The skeleton frames 47 and 48 are spaced apart laterally immediately above the'slots 41 113 and 42, and angle-bar members 76 ar provided on the respective vertical members '50,

51 and 53 to constitute a horizontal track for the rollers 7 7 of a conveyer chain 78-, which is shown generally only in Fig. 3 ofthe draw 11:

ings. It isto beunderstood that any suitable or desired form of chain may-be employed. 1

In general, it may be noted that I prefer to employ two separately-actuatedchains, one

operating or moving over the slot alandthe V f other moving over the slot 12, drums 7 9 and 79a'being1 provided at each end of the furnace around which theconveyer chains'may turn or move, in a manner .well known in the art. I have illustrated the sheaves or drums 79 and479a as provided with gear teeth in orderthat they may be properly driven by a suitable actuating means (not' shown in detail in the drawings) It may be noted that alternately opposite ends of the furnace willbe effective as loading'stations for placing material to be heat treated in the furnace on .the respective-ppo'sitely movingvonveyer chains, the stations for removing thiswmaterial being located at the alternately opposite corners. of the furnacestrueture. V

While'it is within the province of my invention to employ .a single conveyer chain,

the two portionsof'which move over the re spective slots 41 and 42 in opposite directions,

1 I prefer to employ two separate. chains, as this permits ofoperating the two chains at different speeds, whereby it is possible to adapt the furnace to a wider range of work.

This is for the reason that it is frequently possibl to vary the speed of movement of a .conveyer chain in accordance with the type conveyer chains permits of obtaining a' 7 ed, from the convey er 'vals, these being shown in detail in F1gs.

of enamel coating which is being heated in the furnace, so that the use'of two separate greater output from any given furnace.

A plurality of hook holders 81 are suspendchain, at spaced interand 11 of the drawings, As there shown,

. each hookholder includes two similar and opposedpo-rtions 82wl1ich are substantially rectangular in contour, the upper ends of the two members 82 being provided with cooperating lugs 83 and 84 spaced apart to provide 7 a recess-86 between them,-into which theen larged lower ends of the'link member-s87 are fitted. A pair'of bolts 88 extend through the two opposed members 82to securely clamp hook supporting rods to the rods 87. The

lower endsof the members'82 are provided with inwardly projecting lugs 89 from which are supported depending rods 91, shown in .detail in Fig. 7 ofthe drawings. The upper ends of the rods 91'are enlarged-to'substan- =-tia lly rectangular shape, and an opening may be provided therethrough to fit over or'around the-plurality of lugs 89 in order that the rods may have aslight swin ing movement longitudinally of the conveyer chain. The upper ends of the rods 91 are of such shape as to cooperate with the lower surfaces of the lugs 84 to prevent excessive longitudinal swinging movement for the reason that any uneven or jerky movement of the conv'ey'er chain should be transmitted in the least possible degree to the material supported adjacent to the lowerends'ofthe rods. a,

. 'Links '93 extend between adjacent rods 91 and are supported upon foo't plates or blocks 9 1 with which the lower ends of the rods are provided. Cooperating pins and sockets may be provided in the respective members 9 1:and

93 in order to ensure that the links 93 shall not become disengaged from the'rods 91.

I The material itself may be supported from I cross bars 96, shown more particularly in Fig. 8 of the drawings, which areof'such construe tion as tobe easily and quickly mounted on or above the links 93 and to extend laterally therefrom. A'plurality of holes 97 are provided in the members 96 to receive the upper ends of metal hooks 98 11pon which the material to'be enameled'may be hung. As the sizes and shapes of the articles to be enameled or otherwise heat treated may vary greatly,

the members 96 are madein substantiallythe shape shown in Fig. 8 in-order that the spacing between them and, therefore, betweenthe hooks 98, may be such as may be desired.-

Tlhe members 58, each 'o'fsubstantially' Z- shape and defining the upper edges of the walls of the slots 11 and -12, are severallyv provided with I dust-collecting grooves 101 in" means arealso provided inthe form 'of'relatlvely narrow elongated metal plates 1"2, one of the ends of each of the plates being bent laterally out of the normal plane of the plate;

in substantially themanner'shown in Fig. 7 of the drawings. Each plate 102 is provided with openings through which the upper end portions of the rods 91 may extend. During the normal operation of the furnace, the plates 102 rest upon the intermediate webs-of the members 58, which members, as shown in Fig. 1 of the drawings, extend not only along the length of the furnace structure but also over all of the path traversed by the conveyor" chain. 7 I v While no specific details of the means for supporting the members 58 beyond the furnace structure are shown, it is to be understood that suitable supporting means are provided and are spaced suitable distancesa art. Since dust is alwayspresent'int e atmosphere and may drift downwardly through the slots 11 and 42 and possibly settle upon the articles undergoing treatment and thus impair their appearance, the'dust grooves 101 in the members 58'and the plates 102 which to cover these grooves are provided to insure that the dust shall be caught in the grooves instead of being permitted to fall through the slot end of the mass 36 of concrete but also the upper end of themem-bers as. Material-of this kind is providedat thispIacein ordertO their upper horizontal surfaces; Slot-closure permitof vertical movement of the members 43 relative to the members 158, j that is, any unequal expansion or contraction or'relati've' movements of these members of thefurnace structure will be of no effect, so far asalign; ment of these members is concerned, so that.

from which suitable resistor members 107 may be suspended. Refractory spacing memhere 100 are also provided in order to ensure that ad] acent parts of the preferably metallic resistor member 107 shall not operatively env gage each other during the operation of the furnace.

It is highly desirable to provide a bottom heating means and, for this purpose, I provide a resistor member 109 which is located immediately above the upper surface of the bottom portion or wall of the furnace and the adjacent convolutions of this resistor member are spaced apart by similar refractory members 108. A floor plate 111, preferably made 'of metal, is supported by suitable refractory supporting members 112 above the resistor 109. I have indicated the electric heating elements generally only and do not desire to be limited to any particular construction ofsuch elem nts, inasmuch as the main object is to obtain substantially uniform heat distribution in the chamber from heaters adjacent to at least three walls of the furnace.

As was hereinbefore stated, the slot-closure plates 102 are to be supported by the continuity of members 58 extending not only over the furnace structure proper but also beyond it. In order to ensure a support for the plurality of slot-closure plates 102, in addition to that provided by the members 58, I have provided, on each of the depending rods 91, an intermediate annular flange 116 so that the plates 102 will be prevented from dropping downwardly upon the rods 91.

It may become necessary to shut down the furnace for repairs to the conveyor chain or chains, and, in order to be able to conserve the heat stored in the structure of the heating chambers, I provide a plurality of swinging doors 121, shown more particularly in Fig. 2

of the drawings, each door being hinged on horizontal trunnions 122 and being provided with a counterweight 123, the door assembly being turned by manual means (not shown) from its normal position, as shown in Fi I 2 of the drawingsg'toa substantiallycupright" nace chambers are substantially closedfl Side-dooropenin'gsl26 are provided adj a.-

cent tothe ends of the heated furnacechanibers, and a door 127, of refractory material,

is providedfor each of the door openings. These doors may move vertically or swing horizontally asmay bewfound desirable and I have not'indicated any specific supporting= means Ltherefor.

position, whereby the ends'of the heated fur- The furnace structure embodying my in ventioni thus {providesa highly eflicient "Wall structure including a numberoflayers or shelvesof different refractory materials, each, beinglocatedin that part ofthe furnace.

structure wherein. it will effect or obtain the istics.

upper: part of the skeletonmetal .frame andparticularly that part located-over the refractory furnace structure being provided I 90 315. skeleton frames effective not only 'to suppor-tf. the conveyer chaimthe material-supporting with a plurality of spaced but cooperating best results according zto its own character--- Aanetallic skeleton frame surrounds the. furnace structure of refractory material, the;

members and the material itself but-opera tive also to 1 support the overhanging parts of the roof structure of the-furnacein such.

manner as topreclud'e appreciable movement c of these parts relative to each other. I have found, in effect, in an actually installed and operated furnace, that the provision of these skeleton frames located within, and adjacent to the top=portion of, the main skeleton fra meensures that the overhan gingroof portions will move buta very small fraction of an,

inch,"if-at all, in spite ofthe fact that the temperature coeiiicients of expansion ofythe different materials-may vary'quite widely.

This.meansthattherewill be little or no shifting of thetroof. structure-relative to the. track located *at :the top of the: skeletons.

frame 7 structure and it is, therefore, possible to vary the temperature of the-furnace ChalTL- ber-in accordance Wlth possible demands for:

suchchange or to shut down tliefurnace and then-start the same again without experiencing any trouble because of mechanical engagement of the movingparts and the sta iisit tionary parts by reason of such relativeex- I pansive or contractive movements ThQ'SlOb-LClOSIlIG'PlfilZGS 102 are movedlby therods 91. but are supported by the furnace structure to not only close the slots 11 and 42 but also to prevent dust particles fronlsettling on the work being-carriedfthrough the.

furnace chambers so that a relatively large proportion of perfectly enameled material is ensured( Since various modifications may be in the device embodying my invention, Igdesire that {only fsuch limitations i shall be 1 placed thereon as are imposed by'the prior art or are set forth in theappended claims.

I claim as my invention: 7 1; A tunnel furnace having outside walls of predetermined length and an inside wall of shorter length, a concrete base structure for 1) all of said walls, and means anchored in said concrete base structure at the end of theinside wall for preventing free longitudinal eX- pansi-on of said inside wall at its upper part.

2. A tunnel furnace having solid outside walls of predetermined length and an inside wall of shorter length and including a plurality of arched portions, a concrete base structure 'for'all of said walls, and means tion overhanging one of said furnace chambers, three diagonally-braced box-like frames i above said roof structure and supported by the skeleton metal frame, and resilient means supported from the box-like frames and supof the roof structure.

In testimony whereof, I'have hereunto sub-' this 28 day of Feby.1930 JAMES C. WOODSON.

scribed my name anchored in the concrete at the end of said inside wall for forcing the longitudinal eXpan- 3. A double-chamber I refractory slabs.

4. A tunnel furnace having side walls, a

longitudinally-slotted roof structure including a plurality of horizontally-extending refractory slabs each having an edge portion resting on one of said walls, a plurality of ver- I tically-extending refractory slabs resting on the other edge of said horizontally-extending refractory slabs, and a mass of initially plastic self-hardening material tying together the walland the two sets of refractory slabs.

. 5. A tunnel furnace havinglongitudinally I extending walls, and a skeleton metal'frame at the sides and the top of the furnace, a roof structure havinga longitudinal slot and comprising horizontally-extending slabs of vrefractory material having their respective outer edge portions resting on one of'said walls and their inner edges located in laterally-spaced relation at said slot, verticallyextending slabs of refractory material resting on the inner edge portions of the horizontally-extending slabs at said slot, and metal members of substantially angle-bar shape in lateral section supported by said skeleton metal frame and operatively engaging the upper edgeportions of said vertically-extending slabs to maintain a predetermined disorting the respective overhanging portions tance between the upper ends of said vertical slabs while permitting free vertical expansion thereof; Y 1 f V 6. A double-chamber tunnel furnace having two outside walls and one intermediate wall to constitute two parallel and longitudinallyextending chambers, and a skeleton metal frame, a three-part roof structure, each part having at least one portion thereof supported on one of said walls and having another por- 

